FBI photos show the men suspected in Monday's Boston Marathon bombings. Tamerlan Tsarnaev, who has been called "Suspect No. 1" at left has died, officials said, while Dzhokhar A. Tsarnaev, known as "Suspect No. 2," (right) remains at large.Photo: AP

A night of violence led to a massive manhunt for one of the suspected bombers of the Boston Marathon after his brother was killed in a wild shootout with authorities.

The manhunt in turn led officials to the Cambridge home of Tamerlan and Dzhokhar Tsarnaev, where they evacuated a one-block radius around the home and SWAT teams converged on the area this morning.

By sunset today, cops had yet to get their man.

“We do not have an apprehension of our suspect this afternoon – but we will have one, we’re committed to that,” Massachusetts state police Col. Timothy Alben said.

Cops want to grab their suspect sooner rather than later, fearing what he might do, given the explosives used so far.

The FBI found explosives, synthetic powder and an unspecified number of pipe bombs with fuses in the brothers’ home, according to a CBS News report.

“A bomb tech found a number of pipe bombs already assembled,” CBS News John Miller reported. “Whatever else they saw gave them enough concern about moving this material.”

Alben said he believes the suspect was still in the Bay State tonight — and not much further than Boston or its suburbs.

“I don’t have any direct knowledge that he’s in the Boston area. But we don’t think he’d get much further,” Alben siad. “His ties seem to be here.”

As cops searched high and low for the suspected bomber, police announced they’d conduct a “controlled explosion.”

The explosion was originally planned for this afternoon but the report says that the delay could be the result of finding new materials inside the home that authorities weren’t expecting to find.

Tamerlan, 26, who has been referred to as “Suspect No. 1″ and was seen wearing sunglasses and a black cap in video and pictures – was wounded in a shootout with police and later died at the hospital.

Dzhokhar A. Tsarnaev, 19 (
)

A map of the Watertown neighborhood where SWAT teams and other agencies have swarmed a home. (Google Earth)

The FBI released a new photo Friday of Dzhokhar Tsarnaev. (
)

Sean Collier (
)

His younger brother Dzhokhar, 19, previously known as “Suspect No. 2″ and seen wearing a backwards white cap over his shaggy hair, is still on the loose, Boston Police Commissioner Edward Davis said in an early-morning press conference.

The uncle of suspected bomber Dzhokhar Tsarnaev called his nephews “losers” and told the fugitive suspected bomber to surrender.

“We’re talking about three dead people, 100-something injured, and I do not believe, I just do not believe our boys would do that … I don’t know them in the way that they could be capable of this,” Tsarnaeva said.

Meanwhile, a car registered to Tamerlan was found in Boston, shortly after reports emerged that Dzhokhar may have escaped the perimeter in a gray Honda CRV.

Massachusetts State Police say the pair spent the night in the vehicle and used it to carjack a Mercedes SUV.

Police said Friday morning that one of the brothers stayed with the carjacking victim for a few minutes and then let him go.

They say one brother drove away in the CRV, and the other one drove away in the Mercedes.

Police say one then ditched the CRV and reunited with his brother in the Mercedes. Authorities say both suspects were in the Mercedes when they encountered police in the nearby city of Watertown and hurled explosives at officers.

CNN reported one or both of the brothers threw one grenade and several pipe bombs at police although not all of the pipe bombs exploded.

Tamerlan Tsarnaev was shot and later died from his injuries. Dzhokhar reportedly drove over his brother when he escaped. He later abandoned the vehicle, according to officials.

During the firefight, a second police officer was struck by bullets and taken to the hospital.

Hospital officials said Tamerlan Tsarnaev’s body had a combination of gunshot wounds and blast-related injuries. The Boston Globe reported that an explosive trigger was found on Tamerlan Tsarnaev’s body at the morgue.

Earlier in the night, the two suspects were believed to be involved in the fatal shooting of a campus police officer at the Massachusetts Institute of Technology.

Robert Lamontagne, a university spokesman, declined to comment beyond confirming that Tsarnaev was registered there. He would not immediately say when Tsarnaev enrolled, what subject he was studying or whether he lived on campus.

Earlier, roughly 50 heavily armed officials swarmed a Watertown home on Quimby and Willow Park, along with a large SWAT truck with an officer manning a gun on the turret of the truck.

Tension at the scene has eased as officials are apparently winding down their investigation of the home.

The armored SWAT cars have left the scene and only a few squad cars remain at the home.

Earlier, an officer on a megaphone was heard saying, “If you’re in there, come out” as officials forced a one-block perimeter around the home.

CBS News reported this afternoon that students said they saw Dzhokhar walking around the UMass campus this week after Monday’s blast. A UMass official told The Boston Globe that Dzhokhar apparently used the campus gym and slept in his dorm Wednesday night. A fellow student who did not want to be identified told the newspaper Dzhokhar also attended a party Wednesday night.

The ethnic Chechen brothers are from Dagestan, which neighbors Chechnya in southern Russia. They lived near Boston and had been in the U.S. for about a decade, an uncle said.

Tamerlan Tsarnaev spent the first six months of 2012 overseas.

His US reentry came through JFK from Moscow, law enforcement sources said.

He was apparently not on any terrorist watch list. It wasn’t immediately clear where he went.

Dzhokhar Tsarnaev is a naturalized US citizen — sworn in on Sept. 11 last year.

Ramzan Kadyrov, a political leader in Chechnya, said today: “Tragic events have occurred in Boston. As a result of the terror act people were killed. We have already expressed condolences to the people of this city and to the people of America. Today, as the media reports, one [Tsarnaev] was killed as police tried to arrest him. It would be logical if they were to hold him and investigate him, and determined the circumstances and extent of his guilt. Apparently, security services needed to calm down the public by any means necessary. Any attempt to draw connection between Chechnya and the Tsarnaevs, if they are indeed guilty, is futile. They grew up in USA, their views and beliefs were formed there. It is necessary to seek the roots of this evil in America. The whole world needs to fight against terrorism. We know this better than anyone. We hope for the recovery of all the victims, and we mourn with the Americans. #terrorism #Boston #consequence”

The father of the suspects claims that his son who is still on the loose is a smart and accomplished young man.

“My son is a true angel,” the elder Tsarnaev said told the Associated Press by telephone from the Russian city of Makhachkala . “Dzhokhar is a second-year medical student in the U.S. He is such an intelligent boy. We expected him to come on holidays here.”

Ahidi Moros, who lives near Melendi and Nichols Ave., said he went to high school with the pair.

“I can’t believe this is happening. I’m really not over it. They couldn’t speak English when they first got here. I need to clear my head.”

Details are rapidly coming in from various sources as new information becomes available.

Gov. Deval Patrick said today that a shelter in place order is underway for the entire city of Boston as well as Watertown, Waltham, Newton, Belmont, Cambridge and Allston-Brighton.

Officials are urging nearby residents to stay indoors – and not to pick up any strangers on the side of the road.

Mark Abbamonte, 26, told The Post he was in lockdown at his Watertown home and could see police evacuating people down the street and checking their home.

Abbamonte said the overnight firefight happened just three blocks from his home and “could see all the explosions from my house.”

“I woke up on the third explosion; my roommate heard three explosions,” Abbamonte said. “There were so many [gunshots] I couldn’t even count. I heard cops yelling to someone, ‘get on your knees.’

“It woke me up, I heard [the explosion] and panicked, I didn’t know what it was. I thought it was firecrackers, but with what happened in Boston Monday I knew it could be something.”

“I just hope they catch the second suspect. I’m calmer than I was a few hours ago, but I’m running on adrenaline. It’s been a long night.”

All public transportation in and around Watertown, including Massachusetts Bay Transportation Authority service, was also suspended as a safety measure, Mass. Emergency Management Director Kurt Schwartz said.

Amtrak has also suspended service in the area, according to TV reports.

“We are hoping that as the hours proceed that we will be able to turn back on portions of the system,” Schwartz said. “The system has been shut down now as a safety measure.we are asking people not to wait for public transportation. If you are waiting at a public bus or train station please go home.”

Nearby schools such as Boston University also canceled classes, and businesses are urged to remain closed.

Three people were killed and 176 were injured in Monday’s bombings, which punctured the innocence of Boston’s Patriots’ Day celebrations.

The men were spotted walking down Boylston Street toward the marathon finish line shortly before the pressure-cooker blasts launched shrapnel through the helpless crowd.

Tamerlan Tsarnaev, identified as Suspect No. 1 wore a black jacket, a white shirt, a black hat, khakis and sunglasses. He had a black backpack and appeared to be wearing a Bridgestone golf cap.

Dzhokhar set down his backpack in front of the Forum restaurant, an upscale bar and grill where the second bomb went off, at around 2:50 p.m., feds say.

A photo obtained by The Post shows the suspect at that scene before the blast — with tragic little victim Martin Richard, 8, standing to the left on a police barrier.

Tamerlan was not seen on any of the footage dropping his backpack, authorities said.

The killers used crude bombs made from pressure cookers that were stuffed with ball bearings, nails and other metal items.

At least one of the devices was powered with a rechargeable Tenergy battery that is typically used in such children’s toys as remote-control cars.

FBI agents, in fact, went to several toy stores in Massachusetts and New Hampshire to ask about the battery, employees told ABC News.

Meanwhile, it was revealed last night that a victim who lost both legs in the attack — and who was photographed being wheeled from the scene in a now-iconic photo — provided evidence while still in intensive care.

Jeff Bauman awoke in the hospital and asked for a pen and paper on which he wrote: “bag, saw the guy, looked right at me,” his brother, Chris, said.

Bauman then gave the feds a full description of the man he saw drop a bag at this feet. He said the man wore a cap and sunglasses, a description similar to the FBI’s image of Tamerlan Tsarnaev, his brother said.